{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "\n",
    "\n",
    "## 第二章习题\n",
    "\n",
    "### 一、填空题\n",
    "\n",
    "1.列表的`sort()`方法没有返回值,或者说返回值为________."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "空值"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "2.已知列表 `data=[1,2,30 4]`，那么`data[2:100]`的值为________."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "[30,4]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "3.己知`x=3`和`y=5`,那么执行语句`x,y=y,x`之后，`y`的值为________."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "3"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "4．已知字典 `data= {'a;97, 'A' :65}`,那么`data.get('a', None)`的值为________."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "97"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 二、判断题\n",
    "\n",
    "1.生成器表达式的计算结果是一个元组。`(    )`"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "false"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "2.包含列表的元组可以作为字典的“键”。(  | ) "
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "false"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "3.包含列表的元组不可以作为集合的元素。(   )"
   ]
  },
  {
   "cell_type": "raw",
   "metadata": {},
   "source": [
    "true"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "4．列表的`rindex()`方法返回指定元素在列表中最后一次出现的位置。`(    )`"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "false"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 三、编程题\n",
    "\n",
    "1.输入一个字符串，输出其中每个字符的出现次数。要求使用标准库`collotections`中的`Counter`类,请自行查阅相关用法。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "请输入一个字符串：'1,2,3,4,5,2,1'\n"
     ]
    }
   ],
   "source": [
    "from collections import Counter\n",
    "text = input('请输入一个字符串：')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "X = Counter(text)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Counter({',': 6, \"'\": 2, '1': 2, '2': 2, '3': 1, '4': 1, '5': 1})\n"
     ]
    }
   ],
   "source": [
    "print(X)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "2．输入一个字符串,输出其中只出现了一次的字符及其下标。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {
    "scrolled": true
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "请输入一个字符串：'1,4,5,5,1'\n"
     ]
    }
   ],
   "source": [
    "C = input('请输入一个字符串：')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [],
   "source": [
    "D = [(ch,index) for index,ch in enumerate(text) if text.index(ch)==text.rindex(ch)]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[('3', 5), ('4', 7), ('5', 9)]\n"
     ]
    }
   ],
   "source": [
    "print(D)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "3．输入一个字符串,输出其中每个唯一字符最后一次出现的下标。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {
    "scrolled": true
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "请输入一个字符串'1,8,8,9,4,5,0,4'\n"
     ]
    }
   ],
   "source": [
    "s = eval(input('请输入一个字符串'))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[('1', 0), ('8', 4), ('9', 6), ('5', 10), ('0', 12), (',', 13), ('4', 14)]\n"
     ]
    }
   ],
   "source": [
    "positions =[(ch,index) for index,ch in enumerate(s)\n",
    "if index == s.rindex(ch)]\n",
    "print(positions)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "4．输入包含若干集合的列表，输出这些集合的并集。提示:使用`reduce()`函数和`operator`模块中的运算实现多个集合的并集。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "请输入包含若干集合的列表：[{14,55},{145,556}]\n"
     ]
    }
   ],
   "source": [
    "from functools import reduce\n",
    "a =eval(input(\"请输入包含若干集合的列表：\"))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{145, 556, 14, 55}\n"
     ]
    }
   ],
   "source": [
    "from operator import __or__\n",
    "print(reduce(__or__,a))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "5．输入一个字符串,检查该字符串是否为回文（正着读和反看读都一样的字符串)，如果是就输出`Yes`，否则输出`No`。要求使用切片实现"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {
    "scrolled": true
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "请输入一个字符串'1,5,4,6,9,8'\n"
     ]
    }
   ],
   "source": [
    "str1 = input('请输入一个字符串')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "No\n"
     ]
    }
   ],
   "source": [
    "str2 = str1[::-1]\n",
    "if str1 == str2:\n",
    "    print('Yes')\n",
    "else:\n",
    "    print('No')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 课本上65页课后习题"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "1.可迭代对象"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "2.4"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "3.None"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "4.remove()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "5.[6,7,9,11]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "6.() 键 值 键"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "7.items() key() values()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "8.['dict(zip(a,b))']"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "9.b=a[::3]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "10.5 for i in range(10)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "11.不可以"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "12."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['fagbc']\n"
     ]
    }
   ],
   "source": [
    "data = ['fagbc','aaccbbdd','yjyjyj,koukou']\n",
    "print(list(filter(lambda s:len(set(s))/len(s) >0.5,data)))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "13."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 503, 509, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593, 599, 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691, 701, 709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787, 797, 809, 811, 821, 823, 827, 829, 839, 853, 857, 859, 863, 877, 881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977, 983, 991, 997]\n"
     ]
    }
   ],
   "source": [
    "def prime(x):                       \n",
    "    for i in range(2,x):\n",
    "        if x%i==0:\n",
    "            return False\n",
    "        if i==x-1:\n",
    "            return True\n",
    "output=filter(prime,range(2,1001))\n",
    "print(list(output))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "15."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "16."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "17."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "input your nameXI\n"
     ]
    }
   ],
   "source": [
    "d = {'LI':'1','XI':'2','GUA':3}\n",
    "a = input('input your name')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "2\n"
     ]
    }
   ],
   "source": [
    "print(d.get(a,'您输入的键不存在'))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "18."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 29,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[37, 22, 20, 5, 46, 75, 69, 0, 56, 71, 20, 73, 29, 65, 76, 89, 52, 21, 71, 82]"
      ]
     },
     "execution_count": 29,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "import random\n",
    "s = [random.randint(0,100)for i in range(20)]\n",
    "s"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 31,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[0, 5, 20, 22, 37, 46, 56, 69, 71, 75, 89, 82, 76, 73, 71, 65, 52, 29, 21, 20]\n"
     ]
    }
   ],
   "source": [
    "a = sorted(s[:10])\n",
    "b = sorted(s[10:],reverse = True)\n",
    "x = a+b\n",
    "print(x)"
   ]
  }
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